The "On" and "Auto" settings on an air conditioner (AC) thermostat refer to different fan operation modes. The fan is responsible for circulating air within the room and distributing the conditioned air from the air conditioner throughout the space.
On Setting: When the thermostat is set to "On," the fan of the air conditioner will continuously run regardless of whether the cooling (or heating, if it's a heat pump) function is active or not. This means the fan will keep running even when the desired room temperature has been reached, and the compressor (or heating elements in the case of a heat pump) may cycle on and off to maintain the set temperature. The "On" setting ensures constant air circulation, which can be beneficial for air filtration and even temperatures throughout the room. However, it may result in slightly higher energy consumption as the fan operates continuously.
Auto Setting: When the thermostat is set to "Auto," the fan operates only when the cooling or heating system is actively running to reach the desired temperature. Once the set temperature is reached, both the compressor (or heating elements) and the fan will shut off until the temperature deviates from the set point again. The "Auto" setting is generally more energy-efficient because the fan doesn't run constantly when it's not needed, which can lead to lower electricity consumption compared to the "On" setting.
In summary:
- "On" setting: The fan runs continuously, providing constant air circulation.
- "Auto" setting: The fan runs only when the cooling or heating system is actively running to reach the set temperature.
Which setting to choose depends on personal preferences and comfort needs. The "Auto" setting is commonly recommended for energy efficiency, as it can help save on electricity bills by not running the fan continuously when cooling or heating is not necessary. However, some individuals may prefer the "On" setting for improved air circulation or to balance temperatures throughout the space.